Macdonald N, Elam G, Hickson F, Imrie J, McGarrigle C A, Fenton K A, Baster K, Ward H, Gilbart V L, Power R M, Evans B G
HIV and STI Department, Health Protection Agency Centre for Infections, UK.
Sex Transm Infect. 2008 Feb;84(1):8-13. doi: 10.1136/sti.2007.027946. Epub 2007 Nov 14.
To detect and quantify current risk factors for HIV seroconversion among gay men seeking repeat tests at sexual health clinics.
Unmatched case control study conducted in London, Brighton and Manchester, UK.
75 cases (recent HIV positive test following a negative test within the past 2 years) and 157 controls (recent HIV negative test following a previous negative test within the past 2 years) completed a computer-assisted self interview focused on sexual behaviour and lifestyle between HIV tests.
Cases and controls were similar in socio-demographics, years since commencing sex with men, lifetime number of HIV tests, reasons for seeking their previous HIV tests and the interval between last HIV tests (mean = 10.5 months). Risk factors between tests included unprotected receptive anal intercourse (URAI) with partners not believed to be HIV negative (adjusted odds ratio (AOR) and 95% confidence interval 4.1, 1.8 to 9.3), where increased risk was associated with concomitant use of nitrite inhalants, receiving ejaculate and increasing numbers of partners. Independent risk was also detected for unprotected insertive anal intercourse (UIAI) with more than one man (AOR 2.7, 1.3 to 5.5) and use of nitrite inhalants (AOR 2.4, 1.1 to 5.2).
HIV serodiscordant unprotected anal intercourse remains the primary context for HIV transmission among gay men, with increased risk associated with being the receptive partner, receiving ejaculate and use of nitrite inhalants. Although the HIV transmission risk of URAI is widely acknowledged, this study highlights the risk of UIAI and that nitrite inhalants may be an important facilitator of transmission when HIV exposure occurs.
检测并量化在性健康诊所寻求重复检测的男同性恋者中当前导致HIV血清转化的风险因素。
在英国伦敦、布莱顿和曼彻斯特进行的非匹配病例对照研究。
75例病例（过去2年内HIV检测曾为阴性，近期检测呈阳性）和157例对照（过去2年内HIV检测曾为阴性，近期检测呈阴性）完成了一项计算机辅助的自我访谈，内容聚焦于两次HIV检测期间的性行为和生活方式。
病例组和对照组在社会人口统计学特征、开始与男性发生性行为后的年限、终生HIV检测次数、上次进行HIV检测的原因以及上次HIV检测与此次检测的间隔时间（平均为10.5个月）方面相似。两次检测之间的风险因素包括与不认为是HIV阴性的性伴进行无保护的被动肛交（URAI）（调整后的优势比[AOR]及95%置信区间为4.1，1.8至9.3），风险增加与同时使用亚硝酸盐吸入剂、接受射精以及性伴数量增加有关。还检测到与一名以上男性进行无保护的主动肛交（UIAI）（AOR 2.7，1.3至5.5）和使用亚硝酸盐吸入剂（AOR 2.4，1.1至5.2）存在独立风险。
HIV血清学不一致的无保护肛交仍然是男同性恋者中HIV传播的主要情形，作为被动性伴、接受射精和使用亚硝酸盐吸入剂会增加风险。尽管URAI的HIV传播风险已广为人知，但本研究强调了UIAI的风险，并且当发生HIV暴露时，亚硝酸盐吸入剂可能是传播的一个重要促进因素。
